Padding a String with Printf

ESPHome
1

I have a couple of max7219 matrix displays joined together as a ‘ticker’ that displays text derived from a sensor defined in Home Assistant. When this sensor is longer than the number of characters that can be displayed it scrolls. This is fine, except whatever I do I cannot get a space between the sentences as they scroll across a screen. So instead of:

"This is a message - This is a message"

I get

"This is a message -This is a message".

Here is my display configuration in esphome:

display:
  - platform: max7219digit
    id: max7219digitdisplay
    cs_pin: GPIO5
    scroll_delay: 0s
    num_chips: 12
    scroll_speed: 20ms
    intensity: 1
    lambda: |-

      std::string text = "";

      if (id(display_content).has_state()) {
        text = id(display_content).state.c_str();
      } else {
        text = "No Data";
      }

      it.printf(0, 0, id(display_font), "%s - ", text.c_str());

But it always trims that space after the hyphen. I have tried:

it.printf(0, 0, id(display_font), "%s%.3s", text.c_str(), " - ");`

and

text += "\u2009";  // Unicode thin space

it.print(0, 0, id(display_font), text.c_str());

(This causes problems because i’m using a 8x8 font with a limit character set so not sure if it would work otherwise).

And I’ve tried anything else I can find from Google, ChatGPT and Claude.AI. Padding is usually based on the string being a fixed width but this string could be any length.

Anybody got any ideas?